Injection compression molding method for optically formed product
US6616868B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 2000 |
| Grant date | Sep 9, 2003 |
| Priority date | — |
| Expiry date | Oct 19, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/808
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method of producing an optically molded product of a thermoplastic resin by injection compression molding, the method comprising the steps of:(1) expanding the volume of a cavity more than the volume of the optically molded product of interest;(2) injecting a molten thermoplastic resin into the cavity through an injection cylinder;(3) compressing the expanded cavity to a prescribed thickness of the molded product;(4) returning an excess of the thermoplastic resin produced by the compression into the injection cylinder; and(5) keeping the molten thermoplastic resin in the cavity until the molded product of interest is formed. The present invention makes it possible to produce an optically molded product (for example, a spectacle lens) free from a weld line and excellent in surface accuracy using a metal mold having a simple structure industrially advantageously.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.